public static function moveApplications()
 {
     RecruiterController::requireLogin();
     global $params;
     $selected = MongoIdArray($params['selected']);
     $to = $params['to'];
     $recruiterId = $_SESSION['_id'];
     // Make sure all selected are owned.
     foreach ($selected as $applicationId) {
         if (!ApplicationModel::isOwned($recruiterId, $applicationId)) {
             echo toJSON(['error' => 'permission denied']);
             return;
         }
     }
     // Mark new status.
     foreach ($selected as $applicationId) {
         ApplicationStudent::changeStatus($applicationId, $to);
     }
     return self::ajaxSuccess();
 }